Evaluating Ignition and Combustion Performance with Al-Metal-Organic Frameworks and Nano-Aluminum in HTPB Fuel.

Incorporating aluminum metal-organic frameworks (Al-MOFs) as energetic additives for solid fuels presents a prom- ising avenue for enhancing combustion performance. This study explores the potential benefits of Al-MOF (MIL-53(Al)) ener- getic additive on the combustion performance of hydroxyl-terminated polybutadiene (HTPB) fuel. The HTPB-MOF fuel samples were manufactured using the vacuum-casting technique, followed by a comprehensive evaluation of their ignition and combus- tion properties using an opposed flow burner (OFB) setup utilizing gaseous oxygen as an oxidizer. To gauge the effectiveness of Al-MOFs as fuel additives, their impact is compared with that of nano-aluminum (nAl), another traditional additive in HTPB fu- el. The results indicate that the addition of 15% (mass fraction) nAl into HTPB resulted in the shortest ignition delay time (136 ms), demonstrating improved ignition performance compared to pure HTPB (273 ms). The incorporation of Al-MOF in HTPB also reduced ignition delay times to 227 ms and 189 ms, respectively. Moreover, under high oxidizer mass flux conditions (79-81kg/(m²s)), HTPB fuel with 15% nAl exhibited a substantial 83.2% increase in regression rate compared to the baseline HTPB fuel, highlighting the positive influence of nAl on combustion behavior. In contrast, HTPB-MOF with a 15% Al- MOF additive showed a 32.7% increase in regression rate compared to pure HTPB. These results suggest that HTPB-nAl out- performs HTPB-MOF in terms of regression rates, indicating a more vigorous and rapid burning behavior. [ABSTRACT FROM AUTHOR]